There exists a demand in high technology optical systems, such as in the optical guidance systems for radiation seeking missiles, for a high quantum efficiency, short-time response, solid state detector. The detector must have a high response to near ultra-violet radiation, but be substantially insensitive to radiation in the visible spectrum.
Silicon photodiodes have been proposed for these applications; however, such photodiodes are sensitive to the visible spectrum through approximately 800 nanometers, and therefore must be used in association with optical filtering to remove the visible radiation. Additionally, these detectors have a relatively low quantum efficiency (30% or less).
Cadmium sulfide based solid state detectors have been utilized in solid state radiation detectors; however, the known characteristics of cadmium sulfide detectors suggest that they are useful primarily in the visible range, and are relatively insensitive to ultraviolet radiation. Therefore, it is desirable to provide a solid state detector sensitive to ultraviolet radiation and transparent to infrared radiation, particularly if such a detector can be fabricated to have a relatively small active area so that it may be utilized in conjunction with high resolution optics, and made to have a high quantum efficiency.